1. Field of the Invention
This invention relates generally to a paper handling mechanism of a printer and, more particularly, to an apparatus for accurately and consistently separating and removing a single sheet of paper from a stack of paper and delivering the single sheet of paper to an electrophotographic printer.
2. Description of the Related Art
In the field of printers and photocopiers it is generally desireable that the printer/photocopier have available to it a large supply of standard, blank paper and a mechanism for removing individual sheets of paper from this relatively large supply of paper. Clearly, for the printer/photocopier to work properly, the paper handling mechanism must accurately and quickly remove individual sheets. Numerous devices have been suggested to ensure that only a single sheet of paper is removed from the supply of paper.
For example, Hewlett Packard manufacturers a desktop laser printer under the name Laser Jet.RTM.. That printer includes at least one removable tray, which houses a relatively large supply of individual sheets of paper. When the tray is loaded into the printer, a spring loaded arm enters through an opening in the bottom of the tray and raises the entire stack of paper against the paper handling mechanism. The paper handling mechanism includes a rubberized wheel in contact with the top sheet of paper in the stack of paper. This rubberized wheel is rotated in a direction designed to urge the paper toward the printer and away from the tray. It should be apparent that without some mechanism to retain the lower sheets of paper, it is likely that the rotating wheel would at least occasionally transport more than one sheet of paper into the printer at one time.
Therefore, a corner buckler is employed to retain all but the top sheet of the stack of paper. The corner buckler is a metal or plastic tab that extends over one of the leading corners of the stack of paper. Thus, when the wheel of the paper handling mechanism rotates, the paper is urged toward the printer and beneath the paper buckler. When the force exerted by the rubberized wheel is sufficiently high, the top sheet of paper buckles adjacent the corner buckler and the paper is pulled from the tray while the leading corner of the single sheet of paper contorts around the corner buckler. Once the leading corner of the paper has cleared the corner buckler, the paper returns to a generally flat configuration.
The buckling action of the paper is intended to separate the top sheet of paper from the remainder of the stack of paper. However, the complex contortions forced upon the sheet of paper necessarily limit the speed with which paper can be removed from the tray.
The present invention is directed to overcoming one or more of the problems set forth above.